Automatic magnetic apparatus for simulating radio range signals



oct. 19, R C. DEHMEL AUTOMATIC MAGNETIC APPARATUS FOR SIMULATING RADIORANGE SIGNALS Filed April l0, 1946 2 Sheets-Sheet 1 IN V EN TOR.

ATTORNEY Oct@4 19, 1948.

R. c. .DEI-IM 2,451,927

OMATIC N C AP ATUS FOR MULATIN A 'RANGE SIGNALS Filed April l0. 1946 2Sheets-Sheet 2 v INVENTOR. fic/mrd Car? Ue/111ml ATTORNEY Patented Oct.19, 1948 "UNITED s TATsEs PATENT ,orsi-ce 7 AUTOMATICV MAGNETIC'APPARATUS FOR SIMULATING RADIO RANGEISIGNALS Richard-Carl Dehinel,Summit, N. J.

Application April 10, 1946,-Seria`l No. 660,908

(Cl. 435-Q10) 5 Claims. l

VMvinveution relates 4to `appara'tu'sfor use with aviation trainingAdevices and particularly to meansWhereby-signals adapted to representthose of .an airway radio range system may be automatically vvaried infaccordance with'the course of thesimulated flight .of 1the trainer.

`:In one well-known type `of trainer, standard aircraft instrumentsrAare operated pneumatically and the radio ysignals `are varied manually'by an attending instructor who observes the 4:movement ofiafthree-wheeled traveling Vight path yrecorder and fattenuates thevsignals to `represent those `rec'eived fby ya pilot actually flying thecourse being simulated -by thefstudent In my United States Patent No.2,366,6035granted January 2, 21945 for 4Aircraft'training apparatus, Iihave described another type of aircraft trainer utilizing lapantograp'hic flight course charting device.

It is the Lob'ject of fthe present invention to provide means whereby'the simulated airway radio range signals `of an `aviation trainer areautomatically regulated by :moving 'an attenuating device 'forthesignalswith respect to ya modulatlng surface having aparameter'varyingvaccording to the vlieldstrength distribution of `the airway signals,:the .motion between 'the attenuating--device and the surface :beinglafscanning movement controlled 4by the `travel of `the faircraftposltion .indicating element fof the trainer.

.It fis a feature of my present 'invention that the signals may Vbe'controlled by scanning ,apparatus responsive tto variations in thevpermeance of a magnetic circuit.

` fIt is another 'feature of amy .invention that signals adapted'torepresentthose :tromsseveral radio trans-mit'tersforradio channels, suchas the quadrature A 'and N or iE and T signals of an vairway, may eachbe separately controlled .by a "scanning device and combined .in a,common receiver :circuit for the student.

Another feature lof my invention resides 'in the provision of facilitiesfor automatically operating-'audible or :visual fan and :stationymarkersignals by means of lscanning device operated over :a modulatingusurlace by the movement of the aircraft position `indicating element ofthe trainer.

'These `and many other vfeatures of the invention, :such las novel meansfor introducing 'the effects of wind drift and rotating :the scannedlements to kchange the direction of 'wind'drift will be :more`ac'l'early understood by reference to the following text 4and the`drawing 1in which practical AicoInmercial embodiments :of theinventionV are shown. vIt -is to be clear, of course, that suchillustrations are primarily for purposes of disclosure and that thestructures `mayJce modied in various respects without departure fromvthe; broad spirit -and .scope of the invention hereinafter dened andclaimed.

.This application isa continuation-impart of my :abandoned 4applicationSerial No. 501,009led September 2, 1943 for Automatic signalcontrollingapparatus for aircraft .training devices, which isiinxturnadivision-of the application Serial No. 423,824, `iiled December 20,.1941, that matured into my fabove vreferred `to `Patent No. 2,366,603.

Parts in the specication .and drawing will be identified by :specificnames ,for convenience-but these `are intended to be as l generic vin`their application to similargparts as the art will ,permit.

Like reference characters denote like parts y:in the :jseveral `figuresin the drawing of which:

Fig. l is a plan view of the flight course vcharting` device andtraversing table -of an aircraft trainermodied' to embody Vthe presentinvention Eig. 12,'is a Isectional viewfon line 2-2 of Fig. l and showsthe apparatus 'adapted to a magnetic method of Vsignal controlling.;

Fig. -3z`is a.,perspective sectional View of a inagneticzsignalcontrolling element; l

rEig. 1i-is a partly diagrammatic View of Va controlrand amplifyingcircuit used in the present invention and Fig. '5 is a 4fragmentary Viewof `a pantograph structure `carrying a supplementary coil forfanmarkerrsignals.

The application of the :invention is not to be limited to :anyparticular `type of trainer as it can be adapted to use withelectrically, fluid, or :mechanically operated training systems andwithf-a wariety'of flight-indicating or recording devices. aForconvenience, one form of the invention `will lben-described wherein itis adapted to a; trainer' of the type disclosed in any copendingapplication :refer-red to above. The ilightpath indicator of fthis:trainer :is illustrated in Fig. 1` as :being of thepantograph type. Themain pantograph l5 lcomprises four arms, l, 2, 3, and 4, plvotedtogether.at their junctions by pivots 5,16., E1 and `8. The arms l and 2 haveshort extensions, :9 'and i0, rto the 'endsof which pantograph arm-s HAand I2 Aare pivoted, the latter arms being pivoted `together vat their`junction by a :scanning .element 53|., more .fully `disclosed lin the,following text. Also `apivoted `to the arms I and 2 by pivots I6 andYl1 'are two additional pantognapharms l-B 4and =Iv9 'at thejfunctionpoint of .which is ra scanning element i530.

At the junction point 8 is located a driving head I4 which has a tractorwheel (not shown) driven by a sprocket wheel 2|, Fig. 1, and through thesprocket chain 22, Fig. 1, by the driving sprocket wheel 23, Figs. 1 and2, which is secured to the upper end of the pivot shaft 5, Fig. 2. Thisshaft is mounted for rotation in a bearing secured to the table 24 andis driven by worm gear 25, in turn driven by the worm 26 mounted on theshaft of the motor ASM, which rotates under control of the trainercircuits at a speed corresponding to the speed of the simulated flight.To guide the chain 22, Fig. 1', idler pulleys 3|, Figs. 1 and 2, arerotatably mounted on the pivots 6 and 1 of the pantograph.

The tractor wheel, referred to above, is mounted in a longitudinallydisposed axle rotatably supported in the lower end of the driving headI4 `which is itself rotatable about the vertical axis to orient saidwheel in response to the operation of the trainer in the simulation ofsteering. To rotate the driving head |4, Fig. 1, sprocket wheel 28 isattached thereto and is driven by a sprocket chain 29, driven by adriving sprocket 30, Figs. 1 and 2. Sprocket 30 is mounted to rotatefreely with respect to the pivot shaft '5 and is in turn driven throughbevel gearing 40 and 4 I, Fig. 2, by the shaft 6|, Fig. 1, driven by thesteer` ing motor SM of the trainer. The speed of the steering motor SMis proportional to the turning rate of the aircraft and is controlled bycircuits of the trainer. To guide the chain 29, idler pulleys 42, Figs.1 and 2, are rotatably mounted on the pivots 6 and 1 of the pantograph.

Thus, through the operation of the motor ASM, the driving head I4 isadvanced over the surface of the table 24 at a speed proportional to theindicatedairspeed and is oriented to determine the direction of itsmovement under the control of motor SM, and, because of the pantographicconstruction, the scanning units '530 and 53| are moved proportionatelyover the elements 534 and 535 representing the field of the airwaysystem.

The cord 550 driven by the motor WDM moves the elements 534 and 535 intheir guides 36 and 31 to introduce the effects of wind drift on theradio signals. Pulley 43 is driven by worm gearing 549 from motor WDMand drives the cord 155|) around idlers 44, 45, and 46 supported fromtable 24. The magnitude of wind drift is pro-` portional to the speed ofthe motor WDM. The direction of wind drift is determined by theorientation of elements 534 and 535 which may be angularly adjusted bysuitable means (not shown) for this purpose on their supports in guides36 and 31 respectively.

As is well known, there are commonly two transmitting channels at anairway radio range station. One of these is the A channel whereby codedsignals are directionally transmitted into one pair of substantiallyopposite quadrants, and the other is the N channel whereby coded sig-vnals are directionally transmitted into a second pair of oppositequadrants. The eld strength distribution of the signal in each quadrantis such that the intensity is a maximum along the axis of the quadrant,fading off on either side and also decreasing in intensity with distancefrom the station. It builds up rapidly as the station is approached, therate of build-up increasing to a surge near the center of the stationand then decreasing suddenly to zero to form a cone of silence over thestation.

The variation in signal strength for one of the above described channelsis illustrated by Fig. 3

. plate.

4 wherein the high areas of the plate element 535 for example, representthe regions of maximum signal intensity, and the low areas the regionwhere the signal strength is a minimum. It is possible therefore, torepresent the eld strength distribution of each channel of a radio rangestation by a variably contoured plate, the change in contouring beingthe parameter which represents the change in eld strength. In many rangestations the quadrants of a channel are symmetrical and diametricallyopposed. In other stations the quadrants are dissimilar and subtend anangle other than 180 degrees. Either type of station may be representedby an appropriately contoured Also in some stations the two channelseach subtend an angle of arc such that only two on-course legs-areformed. In any case, contoured plates may be used as hereinafterdescribed to provide an automatic control of the radio range signals intraining apparatus.

Referring to Figs. 1 and 2, the pantograph I5 is operated by the ASM andSM motors, as above described, and includes the scanning elements 530'the contoured elements 534 and A535. Specically,.

each scanning element comprises a pair of coils arranged for variablecoupling as the element scans a contoured surface composed of a magneticmaterial such as iron.

In Fig. 4 there is illustrated one form of fier and signal coding unit548 which may be used. in combination with the scanning coils to providesuitably attenuated and interrupted signals fromv the oscillator 543 tothe pilots headphone receiver 538. The control grids of the thermionictubes 540 and 542 are connected by conductors 649 and 650 respectivelytothe scanning coils. The oscillator has a common terminal connectionwith the coils 655 and 656, its other terminal being connected byconductor 551 to the coding unit 548 which in turn is connected to thecoils and 652 by conductors 555 and 556 respectively. Accordingly,current from the oscillator 543 is transf mitted after proper coding bythe unit 548 to the coils 55| and 652 in channels N and A respectively.The coil 65| is coupled to coil 655 by the iron core 653 to constituteone scanning eley ment, and likewise the coi1.652 is coupled to coilk656 by the iron core 654 to constitute the other scanningv element, Thecores 653 and 654 are constructed so that when in proximity to amagnetically permeable material the mutualvcoupling between the coilsincreases. Hence, Awhen the pickup coils with cores 653 and 654 aremounted on the pantograph I5', Figs. 1 and 2, and are caused to traverseat a constant elevation the contourediron surface 612, Fig. 3, thechangein signal strength at the headset receiver 538 will be determinedby the contour of the iron plate surface 612.v By providing twocontoured plate surfaces "612 and 613, one for each channelfandcontouring each to such shape that when the scanning device '530 or 53|is moved from any one point in-the scanning plane above the plate toanother point, the change in coupling, which in turn produces a changein the inductance of that part of the circuit, will vary the strength ofthe signal in the associated channel by the same rela'-l tiveamount aswould occur when moving between the same corresponding two points on theradio range being simulated.

It will be understood that the arrangement of coils and contoured platesshown in Figs. 1 and 2 is merely illustrative and that this constructionmay be modified in Various Ways. For example,

the scanning 4coils may be .xed and the plates moved instead by thepantograph I 5', or the pantograph may be eliminated and either thescanning or scanned elements may be driven directly by a course chartingdevice, such as the Link recorder cited, referring to U. Sf Patent No.2,179,663.

Fig. 5 illustrates how my invention may be used' to introduce fanmarkers in -a similar manner. In this arrangement, separate scanningcoils which are supplementary to the A and N channel coils are operatedfrom duplicating members of the pantograph. In the interest ofsimplicity a single pick-up element 530 is shown operated from the mainpantograph arms I and 2 lby auxiliary links I8' and I9 so as toduplicate on a larger scale the motion of range scanning coil element530. Fan marker positions on different beams are represented by magneticmaterial, such as iron pieces Fi, F2, F3 and F4 shaped and contoured torepresent typical fan marker signal fields. Accordingly, when thesupplementary scanning coils are operated to the appropriate position,audible and/-or visua1 fan markers signals may be surged in and out bycorresponding variations in the parameter of the scanned element at thelocations where markers are to occur. It will be apparent thatthesupplementary Scanning coils can be used to bring in the fan marker isignals 'by means of a circuit such as shown by Fig. 4 and in general bythe same manner except that two separate channels are not required, Theaudio oscillator will of course operate at a higher pitch, such as 3000cycles, to simulate the usual fan marker signal tone.

In the embodiment of the invention disclosed, audio-frequency electricalcircuits are employed and the circuits each provide a conservativeelectrical system or network; in contradistinction to the employment ofrelatively high frequencies in an electrical system wherein relativelysubstan device adapted to be operated by a pupil withl respect to aposition representing a radio range station, a source of signalsrepresenting those of a radio range, a receiver therefor, and means formodulating the signals comprising a coil movable in accordance withchange in positionof said charting device and a surface composed of amagnetically permeable material and having a con.. tour such that thetraversement of the coil over the surface causes a variation in magneticflux through the coil in the same manner as the signal eld strength atthe simulated radio range changes.

2. In aircraft training apparatus, a flight-path charting device adaptedto be operated by a pupil with respect to a position representing aradio range station, a source of signals representing those of a radiorange, va receiver therefor, and signal modulating means including acoil movable in accordance with change in position of said chartingdevice and means composed of a magnetically permeable material spatiallyrelated to said coil and arranged so that movement of the coil over saidmaterial varies the permeance of the coil flux path according to thefield strength of a simulated radio range so as to cause variation inthe coil magnetic flux in the same manner as the field strength of thesimulated radio range changes.

3. The combination with an aviation ground trainer for simulating theflight of an aircraft, of a position charting device movable in responseto operation of the training device by a student, means having acontoured surface of a magnetically permeable material for representingthe field strength distribution of a radio range over which said deviceis movable, a source of signals representing those of a radio range anda receiver therefor, and a coil movable with respect to said contouredsurface in accordance with movement of said device for causing variationof the inductance of said coil whereby the intensity of the sig- .nalcurrent is varied and the signals modulated accordingly.

e. The combination with an aviation ground i trainer for simulating theflight of an aircraft, of a position charting device movable in responseto operation of the training device by a student, means defining anon-planar surface composed of a magnetically permeable material forrepresenting the field strength distribution of a radio range over whichsaid device is movable, a source of signals representing those lof aradio range and a receiver therefor, and a pair of coupled coils movableas a unit with respect to said permeable material for causing variationof the coil coupling whereby the intensity of the signal current isvaried and the signals modulated accordingly.

5. In aircraft training apparatus, a flight-path charting device adaptedto be operated by a pupil over a surface` representing a radio range,and means for simulating marker signals or the like comprisingmagneticmaterial shaped to represent a marker field pattern and locatedat said surface to correspond to marker signal positions, a source ofsignals representing those of a marker, a receiver therefor, and coilstructure movable with said charting deviec in scanning relation to saidmagnetic material so as to cause variation in magnetic flux through thecoil for modulating the signals in the same manner as the marker eldstrength changes.

RICHARD CARL DEHMEL.

REFERENCES CITED The following references are of record yin the le ofthis patent:

UNITED STATES PATENTS

